"Donald Trump has zero foreign-policy experience," Rubio said during an event in Okatie, South Carolina. "Negotiating a hotel deal in another country is not foreign-policy experience."

He then criticized Trump for using profane language during a recent event in New Hampshire.

"Even in our political culture I teach my kids to be respectful. There are certain words you don't say," Rubio said, adding, "You turn on the TV and a leading presidential candidate is saying profanity from a stage."

"Profanity from a stage," he repeated.

That was a reference to Trump's repetition of a crude statement made at a rally by someone in the crowd about Sen. Ted Cruz (R-Texas). Trump then jokingly "reprimanded" the person for saying it.